An improved support and bearing for mounting the grader blade assembly of a motor grader on the depending support arms of the motor grader circle. Upright bearing housings are mounted on the arms and positioned forward thereof. Each housing has a forwardly open upper jaw and a forwardly open jaw the interiors of which are lined with anti-friction wear strips, and the blade assembly support rails are slidable in the wear strips, the latter being retained by detachable side plates on the housings. One of the lower wear strips is adjustable to maintain a snug sliding fit between the lower rail and all the wear strips in the lower jaws. The wear strips for the upper jaws are mounted in carriers that are vertically movable in the jaws to accommodate lack of parallelism in the support rails.